Determination of Radiation Beam Pattern

1. A method for determining a radiation beam pattern, the method being performed by a network node that serves wireless devices in a cell, the method comprising: transmitting probe signals, the probe signals being orthogonal to cell-specific reference signals (CRS) transmitted by the network node; receiving responses to the probe signals from the wireless devices, wherein each response includes a measurement report based on reception of the transmitted probe signals at each wireless device; requesting at least one further network node serving the same cell to also receive the responses from the wireless devices and to report the responses received by the at least one further network node to the network node; and determining a radiation beam pattern based on the received measurement reports and the responses received by the at least one further network node.

2. The method according to claim 1 , wherein the probe signals are channel state information-reference signals (CSI-RS).

3. The method according to claim 1 , wherein the responses comprise CRS reference signal received power (CRS-RSRP) measurement values.

4. The method according to claim 3 , wherein the responses further comprise channel state information reference signal received power (CSI-RSRP) measurement values.

5. The method according to claim 1 , wherein each measurement report comprises path gain measurements, and wherein determining the radiation beam pattern is based on the path gain measurements.

6. The method according to claim 1 , wherein determining the radiation beam pattern comprises identifying at least one wireless device to be handed over.

7. The method according to claim 1 , wherein determining the radiation beam pattern comprises identifying at least one wireless device of the wireless devices for which a new radiation beam pattern provides at least one of an improved estimated throughput, an improved load balance between network nodes, and an improved signal quality compared to a current radiation beam pattern.

8. The method according claim 1 , wherein determining the radiation beam pattern comprises identifying an impact of a geometry of a cell.

9. The method according to claim 1 , wherein determining the radiation beam pattern comprises determining an azimuth direction and a shape and an elevation direction and a shape for an antenna of the network node.

10. The method according to claim 1 , wherein said transmitting, said receiving, and said determining are repeated for at least two candidate CRS radiation beam patterns.

11. The method according to claim 1 , wherein the probe signals are simultaneously transmitted in at least two different transmission beams.

12. The method according to claim 1 , wherein the probe signals are sequentially transmitted in at least two different transmission beams.

13. The method according to claim 1 , further comprising: transmitting CRS to the wireless devices using the determined radiation beam pattern.

14. The method according to claim 1 , wherein the network node serves the wireless devices in a cell, the method further comprising: requesting at least one further network node covering the same cell to transmit further probe signals and to receive the responses thereto.

15. The method according to claim 14 , wherein the probe signals and the further probe signals are simultaneously transmitted.

16. The method according to claim 14 , wherein the probe signals and the further probe signals are sequentially transmitted.

17. The method according to claim 1 , further comprising: requesting the wireless devices to respond to the probe signals.

18. A method for facilitating determination of a radiation beam pattern, the method being performed by a wireless device that is served in a cell by a network node, the method comprising: receiving at least one probe signal from a network node, each one of the at east one probe signal being orthogonal to cell-specific reference signals (CRS) transmitted by the network node; transmitting a response to the at least one probe signal, wherein the response includes a measurement report based on reception of the probe signals at the wireless device; receiving at least one further probe signal from at least one further network node, each one of the at least one further probe signal being orthogonal to CRS transmitted by the at least one further network node; transmitting a respective further response to each of the at least one further probe signal, wherein each respective response comprises a further measurement report based on reception of a respective one of the at least one further probe signal at the wireless device; and receiving information of a radiation beam pattern from the network node, wherein the radiation beam pattern is based on the measurement report and on each further measurement report.

19. The method according to claim 18 , wherein the at least one probe signal are channel state information-reference signals (CSI-RS).

20. The method according to claim 18 , wherein the response comprises CRS reference signal received power (CRS-RSRP)measurement values.

21. The method according to claim 20 , wherein the response further comprises channel state information reference signal received power (CSI-RSRP) measurement values.

22. The method according to claim 18 , wherein the measurement report comprises path gain measurements, and wherein the radiation beam pattern is based on the path gain measurements.

23. The method according to claim 18 , wherein at least two probe signals are received, and wherein the at least two probe signals are simultaneously received in at least two different transmission beams.

24. The method according to claim 18 , wherein at least two probe signals are received, and wherein the at least two probe signals are sequentially received in at least two different transmission beams.

25. The method according to claim 18 , further comprising: receiving a request from the network node to transmit the response, and wherein the response is transmitted in response thereto.

26. A network node for determining a radiation beam pattern, the network node comprising: a processing unit, the processing unit being configured to cause the network node to: transmit probe signals, the probe signals being orthogonal to cell-specific reference signals (CRS) transmitted by the network node, receive responses to the probe signals from wireless devices, wherein each response comprises a measurement report based on reception of the transmitted probe signals at each wireless device, request at least one further network node serving the same cell to also receive the responses from the wireless devices and to report the responses received by the at least one further network node to the network node, and determine a radiation beam pattern based on the received measurement reports and the responses received by the at least one further network node.

27. A wireless device for facilitating determination of a radiation beam pattern, the wireless device comprising: a processing unit, the processing unit being configured to cause the wireless device to: receive at least one probe signal from a network node, each one of the at least one probe signal being orthogonal to cell-specific reference signals (CRS) transmitted by the network node, transmit a response to the at least one probe signal, wherein the response comprises a measurement report based on reception of the probe signals at the wireless device, receive at least one further probe signal from at east one further network node, each one of the at least one further probe signal being orthogonal to CRS transmitted by the at least one further network node, transmit a respective further response to each of the at least one further probe signal, wherein each respective response comprises a further measurement report on a reception of a respective one of the at least one further probe signal at the wireless device, and receive information of a radiation beam pattern from the network node, wherein the radiation beam pattern is based on the measurement report and on each further measurement report.

28. A non-transitory computer readable medium storing a computer program for determining a radiation beam pattern, the computer program comprising computer code which, when ran on a processing unit of a network node, causes the network node to: transmit probe signals, the probe signals being orthogonal to cell-specific reference signals (CRS) transmitted by the network node; receive responses to the probe signals from wireless devices, wherein each response includes a measurement report based on reception of the transmitted probe signals at each wireless device; and request at least one further network node serving the same cell to also receive the responses from the wireless devices and to report the responses received by the at least one further network node to the network node; and determine a radiation beam pattern based on the received measurement reports and the responses received by the at least one further network node.

29. A non-transitory computer readable medium storing a computer program for facilitating determination of a radiation beam pattern, the computer program comprising computer code which, when run on a processing unit of a wireless device, causes the wireless device to: receive at least one probe signal from a network node, each one of the at least one probe signal being orthogonal to cell-specific reference signals (CRS) transmitted by the network node; transmit a response to the at least one probe signal, wherein the response includes a measurement report based on reception of the probe signals at the wireless device; receive at least one further probe signal from at least one further network node, each one of the at least one further probe signal being orthogonal to CRS transmitted by the at least one further network node; transmit a respective further response to each of the at least one further robe signal, wherein each respective response comprises a further measurement report based on reception of a respective one of the at least one further probe signal at the wireless device; and receive information of a radiation beam pattern from the network node, wherein the radiation beam pattern is based on the measurement report and on each further measurement report.